1. Field of the Invention
The present invention relates to a semiconductor device comprising stacked semiconductor elements.
2. Background Art
FIG. 6 shows one example of a conventional semiconductor device comprising stacked semiconductor elements. In FIG. 6, reference numerals 13a and 13b designate TSOP packages. The TSOP package 13a is mounted on and connected to a mounting board 14 by way of external leads 4a, and the TSOP package 13b is mounted on and connected to the mounting board 14 by way of external leads 4b.
In such a conventional semiconductor device, particularly in the case of a semiconductor device comprising TSOP packages, the outer leads 4a of the TSOP package 13a differ in length from the outer leads 4b of the TSOP package 13b. Therefore, each of these two types of outer leads requires a unique mold for bending outer leads. Further, there are also required peripheral components, such as sockets or trays, assuming different profiles, there by adding to the cost.
With such a conventional stacked mounting structure, a plurality of leads projecting to the outside from two sides or four sides of the package are mounted on the board while they are stacked on top of each other, thereby rendering mounting of stacked semiconductor elements difficult. For this reason, the design of the upper semiconductor package must differ from the design of the lower semiconductor package, thereby making it difficult to reduce the cost of the stacked semiconductor device.